Snowy Owl 24 inches

This Arctic nesting species known as Nyctea scandiaca typically subsists on lemmings, a small rodent of the Arctic tundra. But for reasons still not entirely clear, the snowy owl often winters on the Northern Plains. Some say the owl is simply pursuing abundant prey. Others suggest that the owls migrate south to the Northern Plains to ward off winter starvation when the lemming population declines. At four pounds, this is the heaviest owl in North America.